Hydraulic turbine



l Sept. 2,2, 1936. A PFAU HYDRAULIC TURBINE Filed Deo. 8, 1934 5Sheets-Shea?l l sept. 22, 1936. l

A. PFAU 2,055,134

HYDRAULIC TURBINE Filed Dec. 8, 1954 @MMA 5 sheets-sheet 2 Sept. Z2,1936. A. PFAU HYDRAULIC TURBINE Filed Dec. 8, 1934 3 Sheets-Sheet 3Patented Sept. 22, 1936 f UNITED STATES PATENT oFFicE HYDRAULIC TURBINEArnold Pfau, Milwaukee, Wis., assigner to Allis- Chalmers ManufacturingCompany, Milwautree, Wis., a corporation of Delaware ApplicationDecember 8, 1934, Serial No. 756,640 i4 Claims. (o1. 253-117) Thisinvention relates to improvements in hyand operation in order that eachof the above draulic turbine construction and more particufunctions maybe most effectively performed. larly tomeans for bypassing leakagearound a It is therefore an object of the present inventurbine roto-rupon closure of the gate means tion to provide means permitting thebypassing of 5 controllingthe supply of Water to the turbine rothe flowof water, through the gate of a hy- 5 tor and for bypassing the fullflow through the draulic turbine, around the rotor of the turbine. gate,around the turbine rotor, upon occurrence Another object of theinvention is to provide of large and sudden load changes. means movableinto position to bypass either the It is frequently desired to operate agenerator, whole or a part of the ow of water into a hynormally drivenby a hydraulic turbine, as a modraulic turbine, around the rotorthereof. i l0 tor for the purpose of utilizing the inductive ca- Anotherobject of the present invention is to pacity of the generator to improvethe power provide means associated with hydraulic turbines factor of theelectric distribution line. When the to minimize unavoidable leakageinto the rotor generator is so used as a synchronous condenser, of theturbine when in operation and to prevent l5 only wattless power shouldbe drawn from the the action of such leakage on the rotor when l15 line.The work to be done by the motoring genthe turbine is not producingpower. erator should therefore be minimized and should Another object ofthe invention is to provide be limited to overcoming friction andwindage in means controlled by the gate of the turbine to the generatorand the turbine. The gate conprovide a bypass around the turbineoperable trolling the supply of Water to the turbine rotor immediatelyand opening fully upon closure of 20 should therefore be closed astightly as possible the gate and so arranged as to accommodate the buteven such tight closure, in the present gate full ilow. constructions,is not suicient to prevent such Another object of the invention is toprovide amount of leakage therethrough as suilices to means operable bythe pressure from he source accumulate a mass of water in the turbinerotor. of water supplied to a hydraulic turbine and con- 25 Such mass ofwater is then carried around in the trolled by the gate regulating suchsupply to conrotor and greatly increases the load thereon trol the pathof water flowing through the turbine. which reduces the effectiveness ofthe generator Another object of the -invention is to provide acting as asynchronous condenser. a hydraulic turbine structure with means for by-50 AIlOtheT plOblem erlCOllllteled in the Operation passing the leakagethrough the water shutoff 30 0f hydraulic turbines and paI'CulaTly inUI- gate upon closure thereof to avoid action of the bines of thereaction type, is the problem of serotor upon such leakage. curingsuiciently rapid response of turbine op- Objects and advantages otherthan those above eration to changes in load and particularly to setforth will be apparent from the following de- ;,5 load decreases. It isimpractical and even danscription when read in connection with theacgerous to attempt to decelerate the flow of Water companying drawingsin which: quickly enough to have any eiect when the load Fig. 1 is apartial vertical sectional view of a decreases largely and suddenly.Means must hydraulic turbine of the reaction or Francis type thereforebe provided to bypass the full flow of illustrating one embodiment ofthe invention apio water through the gate, around the turbine, impliedto the usual form of reaction turbine Operat- 4o mediately upon theoccurrence of load decreases ing Within a guide CaSe for .radiallydirecting the and such action, to be eifective, must take place W 0fWater luto .the tu'pme? even before the gate means have begun to have F1g' ,2 1s a' partlal Verplcal S,eCt10na1 V1eW of a throttling effect onthe flow, Thus the bypassil modlled fOIm of tlllle ,Wertxon apphd lo a'*lo ing means must be quick acting whereas the shutydraillc turbme of t.e p1 Qpe 1er or Nag er me 45 oi means or gate should bD relatively slowactto Whlch .Water ow-1s dehvered through a' d1" Th bl h 1d r p returnto .t agonal or inclined guide case by which the water ing". "e ypass .Sou ,O. 00.11 s l s is given both an axial and a radial component ofinitial or ineifective position immediately upon flow into the turbine;and

.Complete Closure of the gate Fig. 3 is a, partial sectional view of amodified 50 v Both of the probgems above mdmated. can be form of theinvention adapted to provide a bysolved by means which are .generallysimilar and pass for the entire flow through the gate of the whichoperate in a similar manner. To attain turbine and arranged to Opencompletely and imthe desired result, it is however necessary thatmediately upon beginning of full closure of the such means differ indegree as to construction turbine gate. 55

Referring more particularly to the drawings by characters of reference,the reference numeral 6 designates a portion of a spiral casing to whichwater is delivered from the usual penstock (not shown) and whichsupplies water through a speed ring, formed by the upper and lowerportions 'I and 8, to the rotor of the hydraulic turbine. A plurality ofvanes ll are mounted on stems I2 which are rotatably mounted in thespeed ring and extend upwardly beyond the speed ring for connection withoperating means by which theY vanes may be moved to throttle or shut offthe flow of water to the turbine. An annular cover plate I3 is securedon the speed ring portion l or may be formed as an extension thereof ifso desired. The lower speed ring portion 8 is joined with a dischargering i4 which is preferably connected with a liner I6 for the draft tubeof the turbine. The structural portions above identified substantiallyform a casing into which a shaft I'I extends, which shaft is rotatablein a bearing I8 mounted in the cover plate I3. The shaft supports a huband disk 2 I' from which extend vanes 22 having the outer ends thereofjoined by a discharge band or shroud 23, all of which portionsconstitute the turbine rotor or runner. Water flowing from the spiralcasing 6 through the speed ring- T, 8 flows through the runner vanes 22and discharges through the discharge ring I4 into the draft tube I6.Rotary motion imparted to the runner vanes by such water flow istransmitted by the shaft i l to any suitable driven mechanism which isusually an electric generator.

The flow of water through the speed ring 1, 8 is controlled by theposition of the gate vanes II which are operable from a shifting ring 23through suitable links 2T connecting the shifting ring' with the gatevane stems I 2. The shifting ringV is mounted onthe cover plate I3 andis preferably operable by servo-motors responsive to the rotor speed asis well known and therefore not shown. y The discharge ring I4: isformedwith an annular recess which forms a cylinder 3l in which isi mountedv apiston 32 having opposing diiferential surfaces 33 and 34 to whichpressure may be applied within the cylinder. It will be understood thatthe piston 32 is annular to fit in the cylinder 3I and it will be seenthat the piston surface 33? is much greater than the surface 34. Thewalls of the cylinder 3! are parallel with the axis of the shaft I'I andthe piston 32 must therefore m'ove in a direction parallel to the axisof the shaft'. The runner shroud 23' is formed with a surface 36 at anangle to the axis of the shaft I 'l and the surface 3l of the piston 32is formed at a similar angle to minimize the space between the surfacesv35 and 31 when the piston 32 is raised aswill be described. The pistonsurfaces 33V and 34' aref joinedY by apertures 4I and the cylinderVspace above the piston surface 34 communicates with the spiral casing 5by passageways 42 formed in the speed ring portion 8. Water underpressure may thus flow from the spiral casing S through the passageways52 and the apertures 4l below the piston surface 33. Such water may bedischarged from below the piston 32 tothe tailrace (not shown) by aconduit or conduits 43 controlled by a Valve 44 which is operable bysuitable means responsive tothe position of the g'atevvanesv I I'.

As shown in Fig. 1', such` valve operating means comprises an electricalsolenoid 36, the coil of which is energized from a source of electriccurrent such as the battery 41 upon bridging of the contacts 48. Acontact bridging member 5I is pivotally mounted at 52 and is in the formof a bell crank lever. An arm 53 is mounted on a gate vane stem I2 or onthe arm 21 thereof and carries a roller 54 preferably adjustably mountedon the arm, which roller engages with the lever 5I upon movement of thegate vanes to thereby close the contacts as will be apparenthereinafter.

When the gate vanes Il are moved into the position shown to shut off theflow of water into the turbine, the impossibility of completely shuttingoff such flow (with the present type of vane construction) permits aquantity of water to enter the runner. Such leakage through the gate isundesirable when the turbine is to be at standstill and is particularlyobjectionable when the turbine is being operated by the generator as asynchronous condenser because of the power loss entailed. The roller 54is then so adjusted as to engage the lever 5I to cause such lever tobridge the contacts 43. YSolenoid 46 is therefore energized and thevalve 44 islifted to discharge the pressure applied to the pistonsurface 33 throughy the passageways 42 and the apertures 4I. Anypressure previously present under the piston surface 33 is thereforerelieved and pres'- sure from the spiral casing, always acting throughthe passageways 42 on the piston surface 34, aids the weight of thepistonin forcing the piston into the position shown. Leakage through thegate IIv then ows through the liberal space between the piston 32 andthe discharge band 23 without enter-ing or in any way disturbing therotation of the turbinerunner.

After the gate vanes have been moved' into a predetermined openposition, the roller 54 leaves the lever 5I and the lever drops.Solenoid 46 is then deenergized and valve 44 closes. Continued supply ofwater through the passageways 42 and the apertures il below the pistonsurface 33 now builds'up pressure and, as soon as the unit pressureunder the surface 33 approaches the unit pressure on surface 34, thelarger surface 33 overcomes the weight of the piston and the action ofthe surface 34 thereby causing the piston 32 to lift. Lifting of thepiston 32 continues until the piston surface 34 contacts with the speedring `portion 8 whereupon the piston surface 3l is in close proximity tothe discharge band surface 36. A slight clearance between the surfaces33 and 3l is of course necessary but the quantity of water leakingthrough such clearance space is very much reduced by the provision ofcircumferential grooves in the discharge band surface and the pistonsurface 31 which grooves act as seals in the well known manner.

The construction illustrated in Fig. 2 differs from that above describedin such structural details as are requiredV by the diagonal speed ringconstruction as Well as by the diierences Ydue to theY use of thepropeller type turbine and due to mechanical operationY of the dischargevalve. The shifting ring 23 is now preferably mounted cn the speed ringas being the most accessible location therefor. The piston 32 isformedsomewhat differently frorn the construction illustrated in Fig. 1 butfunctions as previously described. Discharge of leakage through theconduit 43 is now however controlled by a valve 'Il which is rotatedinto open and closed position by a direct mechanical connection of thestem of the valve with an extension 'I2 of the gate vane stem I2 by anysuitable means such as the gears 13 and 14. The spiral casing 6 isconnected with the smaller surface of piston 32 by a conduit 'I6 ratherthan-by a passage' formed in the speed ring. Y

The operation of the modified form of the invention is similar to thatpreviously described except that rotation of the gate vanes A|| into theclosed position rotates the gear 14 which rotates gear 'I3 to open thevalve 1I. Pressure is then discharged through conduit 43 as previouslydescribed and the piston 32 drops away from the position shown whichallows leakage through the gate to ow through the space between the endsof the rotor vanes 62 and the outer surface of the piston 32.V When thegate is open the valve 1| is closed and pressure is built up in thecylinder 3| to act on the piston surface 33 to raise the piston andthereby close off the space between the rotor vane ends and the pistonto prevent any leakage therethrough during power producing operation ofthe turbine. A ring may be removably mounted on the outer surface ofpiston 32. Such construction permits high 1inishing of the ring andmaterially simplifies manufacture of the piston.

In the modified form of the invention illustrated in Fig. 3, thedischarge ring |4 is formed with a plurality of apertures 8| through thebody of the ring and forming discharge ports from the cylinder 3| formedin the ring. The piston 32 is formed as before with the differentialsurfaces 33 and 34 and is provided with apertures 82 therethrough whichare` so located as to shut off apertures 8| when the piston 32 is in itslowermost position shown and to register with apertures 8| when in theraised position of the piston. When the piston 32 is raised, flow ofwater to the turbine rotor is shut oif and all of such flow is `bypassedaround the turbine rotor through the plurality of passageways formed bythe registering ports 8| and 82.

Flow of fluid from the spiral casing 6 to differential piston surface 34and from such surface to piston surface 33 is controlled by a valve 83which connects the upper and lower cylinder portions and allowsdischarge therefrom. The valve 83 is controlled by a floating lever 84connected with piston 32 and with the differential piston of aservo-motor 86. Fluid pressure applied to servo-motor 86 Ais controlledby a pilot valve 81 provided with an inlet 88 to the valve, a pluralityof ports 9| and 94 and outlets 89, 92 and 93 from the valve. The pilotvalve is connected with a suitable pressure source (not shown) by way ofinlet 88. The pilot valve also controls the application of Viiuid to thedifferential pistonl of the servo-motor 96 which controls the openingand closing movements of the gate vanes The pilot valve 81 is controlledby the movement of the speed governor 91 by way of a floating lever 98having one end thereof connected with another floating lever 99. Lever99 is connected by way of a bell crank |8| with the gate vane shiftingmechanism and with a rod |82 connected with the piston of servo-motor86.

As long as the speed of the turbine remains constant and no change ofthe gate vane setting is required, the speed governor holds valve 81 inthe position shown. Pressure through inlet 88 acts through outlet 89 andport 9| while outlets 92 and 93 and port 94 are shut oif. Such pressureacts on the smaller surface of the pistonservo-motor 96 and on bothsurfaces of the piston of servo-motor 88. Servo-motor 96 then holds gatevanes in the position shown and Aservo-motor 86 is biased upwardly totend to lift the piston of valve 83 thereby relieving pressure undersurface 33 to keep bypass 8|, 82 closed thus allowing full passagebetween gate vanes and runner 22. Water under pressure acting throughconduit 16 on surface 34 of piston 32 retains the piston in the positionshown. For slight or gradual changes of load, speed and rgate vaneYsetting; only the servo-motor 96 is affected while the position ofservo-motor 86 remains unchanged.

When a large and sudden speed increase takes place, the piston of pilotvalve 8l may be raised to open port 94 to such extent as to connectportY 9| with outlet 92. Servo-motor 96 then closes gate vanes and thepressure under the large surface of the piston of servo-motor 86discharges. The pressure remaining on the smaller surface of the pistonof servo-motor 86 depresses the piston and causes valve 83 to connectconduit 16 with larger surface 34 of the piston 32 which is raised tocause registering of port 8| and 82 and to bypass water flowing throughthe turbine. When the speed again approaches normal, the piston of thepilot valve 81 returns to the position shown which causes servo-motor 96to return to the position shown. Servo-motor 86 then lifts the piston ofvalve 83 to allow discharge from beneath surface 33 of piston 32 and thepiston returns to the position shown.

The present invention therefore provides a construction for bypassingundesired and unavoidable gate leakage from a hydraulic turbine or tobypass all of the water around the turbine runner without in any wayaffecting the movement of the runner and by means which minimize thenon-power producing leakage of water through the turbine during powerproducing operation thereof. Such means provide a relatively quickacting control of the path of water flow through the turbine and suchpath is controlled responsive to operation of the turbine gate beyond apredetermined point. The flow path controlling means are operable solelyby the penstock pressure and therefore do not require the provision ofan auxiliary source of power for the operation thereof.

Although but a few embodiments of the present invention have beenillustrated and described it will be apparent to those skilled in theart that various changes and modifications may be madethereinwithoutdeparting from the spirit of the invention or from thescope of the appended claims.

It is claimed and desired to secure by Letters Patent:

1. In a hydraulic turbine construction, a source of water underpressure, a rotor operable upon supply of water thereto from saidsource, a gate operable to control the supply of water from said sourceto said rotor and arranged to substantially shut off the flow of waterthereto, a member movable into and out of cooperative relation with saidrotor to provide a by-pass around said rotor for flow of watertherethrough, and hydraulic means controlled by movement of said gate tocause movement of said member.

2. Ina hydraulic turbine construction, a source of water under pressure,a rotor operable upon supply of water thereto from said source, a gateoperable to control the supply of water from said source to said rotorand arranged to substantially shut off the ow of water thereto, a membermovable into and out ofcooperatve relation with saidzrotor to provide aby-pass around. saidrotor for ow of water. therethrough, and hydraulicmeans connected with said Isource and controlled by movement of saidgate to cause movement of said member. f I Y 3. .In a hydraulic turbineconstruction,v a source of Water under pressure, a rotor operable uponsupply of water thereto'from said source, a gate operable to control thesupply of water from said source to said rotor and arranged tosubstantially shut off the flow of water thereto, anda member havingapertures therethrough and movably arrangedv in the space between saidrotor and said gate to bypassA flow of water around `said rotor, andhydraulic means connected with said source and controlled by movement ofsaid gate to cause opening of the apertures through said member tobypass ow of water around said rotor.

4. In a hydraulic turbine construction, a source of water underpressure, a rotor operable 'upon supply of water thereto from saidsource, a gate operable to control the supply of Water from said sourceto saidrotor and arranged to substantially shutoff the flow of waterthereto, and a substantially cylindrical member havingaperturestherethrough and movable into position between said rotor and said gateto direct the flow of Water through said gate entirely around andWithout contacting said rotor.

5. In a hydraulic turbine construction, a source of wat-er underpressure, a rotor operable upon supply of water thereto from saidsource, a gate operable to control the supply of water from said sourceto said rotor and arranged to substantially shut'oi the flow of waterthereto, and a member movable into and out of proximity with said rotortofbypass leakage through 'said gate around and without contacting saidrotor upon movement of said member away from said rotor.

6. In ahydraulic turbine construction, a source of water under pressure,a rotor operable upon supply of water thereto from said source, a gateoperable to control the supply of water' from said source to said rotorand arranged to substantially shut off the flow of water thereto, amember movable into and out of proximity with said rotor to bypassleakage through said gate .around and without contacting said rotor uponmovement of said member away from said rotor, and means for controllingthe movement of said member.

7. In a hydraulic turbine construction, a source of water underpressure, .a rotor operable upon supply of water thereto from saidsource, a gate operableto control the supply of water from said sourceto said rotor and arranged to substantially shut off the flow of waterthereto, a member movable into and out of proximity with said rotor tobypass leakage through said gate around and without contacting saidrotor upon movement of saidv member away from said rotor, and means forcontrolling the movement of said member responsive to movement of saidgate.

8. In a hydraulic turbine construction, a source of water underpressure, a rotor operable upon supply of water thereto from saidsource, a gate operable to control the supply of water from saidsource'to said rotor and arranged to substantially shut olf the iiow ofwaterthereto, a diierential piston arranged for movement into and out oflproximity with said rotor to provide and to close off a passage forleakage through said gate without contactingrwith .said rotor, saidpiston being operable by pressure from said source, and means forcontrolling the action of the pressure in response to movement of saidgate.

acuarela v.9.; In a hydraulicv turbine construction, a source of waterunder pressure, arotor operable upon supply of water thereto from saidsource, a gate operable to control the supply of water from said sourcetosaid rotor and arranged to substantially shut oiI the ow of waterthereto,v a diierential piston arranged for movement into and out .ofproximity With-said rotor to provide and to close olf a-passagefor-leakage through said gate Without contacting with said rotor, saidvpiston being operable by pressure from said source, and means connectedwith said gate and. operable after a predeterminedl movement. thereof tocontrol the applicationv of pressure to said piston.

10. In a' hydraulic turbine. construction, va source of water underpressure, a rotor operable upon supply ofwater thereto from said source,a gate operable to controlthe supply of water from said source to saidrotor and arranged to substantially shut oli the owo-f water theretogfadifferential piston arranged for movement into and out. of proximitywith said` rotor to provide and to close off a passage for leakagethrough said gate without contacting with said rotor, said piston beingoperable by pressure from said source, passageways connecting thesurfaces of said piston with said source beyond said gate, and meansconnected'with said gate andl operable after a predetermined movementthereof to control the application of pressure through said passagewaystosaid piston. v

11. In aV hydraulicV turbine constructiom a source of water underkpressure; a rotor operable upon supply of water thereto from saidsource, a gate operable to control the supply of Water from said sourceto said rotorv and arranged to substantially shut oi the ilow of waterthereto, a Vdiirerential piston arranged for movement into and vout ofproximity with said rotor to provide and to close off a passage forleakage through said gate without contacting with said rotor, saidpiston being operable byY pressure from said source, passagewaysconnecting the surfaces of said piston with said source beyond saidgate,r a valve controlled by said gate to control the application ofpressure to said piston through said passageways after a predeterminedmovement of said gate.

12. In a` hydraulic turbine construction, a source of Water underpressure, a rotor operable upon supply of water thereto Yfrom saidsource,'a gate operable to control the supply of water from said sourceto said rotor and arranged to substantially vshutv oi the ilow of waterthereto, Va

differential piston arranged for movement into and out ofproximity withsaid'rotorV tof provide and to close oil. a passage forleakage throughsaid gate without contacting with said rotor, said piston being operableby pressure from said source, passageways connecting the surfaces ofsaid piston with said source beyond' said gate, a valve controlling thedischarge of pressure from said piston, and means for opening said valveupon closure of said gate beyonda predetermined point.- i 'Y V13. In ahydraulic turbine construction, a source of water under pressure, arotor operable upon supply of water thereto from said source, a gateoperable to control the supply of water from said source to said rotorand arranged to substantiallyV shut off the flow of waterthereto, a.diierential piston arranged for movement into and'out ofxproximitywithsaid rotor tol provide and to close olf a passage for leakageV throughsaid gatewithout contacting with said rotor, said piston being operableby pressure from said source, passageways connecting the surfaces ofsaid piston with said source beyond said gate, a valve controlling thedischarge of pressure from said piston, and electrical means for openingsaid valve upon closure of said gate beyond a predetermined point.

14. In a hydraulic turbine construction, a source of Water underpressure, a rotor operable upon supply of water thereto from saidsource, a gate operable to control the supply of water from said sourceto said rotor and arranged to substantially shut ofi the oW of Waterthereto, a

diierential piston arranged for movement into and out of proximity withsaid rotor to provide and to close off a passage for leakage throughsaid gate without contacting with said rotor, said piston being operableby pressure from said source, passageways connecting the surfaces ofsaid piston with said source beyond said gate, a valve controlling thedischarge of pressure from said piston, and mechanical means for openingsaid valve upon closure of said gate beyond a predetermined point.

ARNOLD PFAU.

